Gasdynamic structure of a supersonic flow around a heat source

A gasdynamic structure arising in a supersonic flow around a heat source is experimentally studied. The heat supply was organized by activating breakdown plasma with focussed radiation from a CO2 laser operating in a pulsed-periodic mode. The repetition frequency of the pulses is found to have a profound influence on thermal-wake formation. On attaining the M = 2.0 flow velocity at a pulse repetition frequency higher than 40 divided by 50 kHz, the thermal wake acquires a continuous structure and the flow regime becomes quasi-stationary. Based on the experimental study performed, a heat-source model was proposed, which was subsequently used in numerical simulations. The numerical results allowed us to trace the time evolution of the thermal wake and elucidate the following characteristic features of its formation: origination of a jet flow at the initial stage of energy supply, formation of a wake periodic structure, and spreading of shock-wave processes from the heat-supply region. Detailed information on the distribution of flow parameters in the wake was obtained. The reliability of results is confirmed by their good agreement with experimental data. A possibility is shown to explain the better air-hydrogen combustion during its initiation with a heat source by intensification of mixing with vortex structures.